How would you design a two nuts jammed against each other thumbwheel (I need the countersunk head at the other end and still be able to rotate the bolt through a hex coupler). Here’s the (complicated?) way I have quickly sketched it:
I want to be able to undo the nuts so I will not glue the two halves together. I’d like to do it without the 3xM3x10mm bolts+nuts but have no idea how.
This is how a lot of people make phase adjustment setups, basically exactly like this design.
Can you tell me what you mean when you say you want to rotate the bolt through a hex coupler and how that impacts the design of the thumbwheels? With your current design, once you’ve secured the bolts in the wheels, does it allow you to rotate the bolt as desired? What modification would prevent the bolt rotating?
Is it correct to believe that the rotation of one thumbwheel relative to the other has to be infinitely variable and having indexed or stepped rotation of those wheels would not work?
Unrelated, is there a way to get notifications of comments to a post to which I’ve not made a comment? Obviously, this post will be sending me notifications of new comments, but if I had not commented, how could I get those new comments via email?
@John_Bump Phase adjustment for nuts? I now realize this can be used as an antibacklash system (maybe)… but I was hoping for a simpler design which I am unable to imagine.
I thought it was an anti-backlash device. I did a quick Thingiverse search using anti-backlash and found a couple posts that resemble your drawing. You may find some ideas in others’ work, even if your design isn’t for anti-backlash.
@Fred_U
I have the bolt running through a hex coupler and I need to be able to screw/unscrew it through the coupler but the countersunk head is hidden so I have to “create” another fixed “head” on the other side, which I am doing via 2 jammed nuts. I can’t revert the bolt due to design.
I did this previously by cutting with dremel a flathead screwdriver slot but that is not as easy as having a thumbwheel rotating it.
PS:I have no idea about getting emails for posts you have’t partici[ated in … maybe “+1” it.
Your explanation is quite enlightening. Your dual thumbscrew idea is quite clean. I don’t think you need the bolts holding the two wheels together, unless you feel the wheels will fall off the nuts. I use two nuts engaged in the same manner frequently for almost the same reason you’ve described, although I don’t need the convenience of the thumbwheels. With a pair of wrenches, the nuts can be jammed tightly and securely. One could place a split washer between the pair, or the more expensive and more secure serrated nord-lock washer and design around that with the thumbwheels.
In that type of configuration, you could have the wheel thicker than the nut with the recess holding the nut in the thumbwheel pointing outward. That’s not very clear. Consider that the top nut on the threaded portion is visible and that there is a thin layer of thumbwheel under it. The other thumbwheel has a thin layer with the nut below that. The layer would be “punctured” with a hole to give clearance to the selected lock washer.
If your recesses were even less deep, enough nut would protrude to allow you to apply wrenches on each nut, to give even more torque to secure them.
I hope if ever I need to have this level of convenience that I remember this discussion. It would be great to build something like this, but even better to have a use for it, which I do not now have.
@Florian_Ford It might be easier for people to understand what the issue is if you were to take a photo of the existing setup – If they can see the whole “picture” then they might be able to suggest something else and/or make recommendations for how to proceed.
@Fred_U Yeah, if the two nuts are well jammed against each other there would be no need for the M3 bolts. I see that some of each nut should be left visible from under the thumbwheel to be able to re-tighten if necessary. But that would be a problem because the thumbwheel would be free to fall, while in my design the upper side of the thumbwheel rests on the upper nut.
But I you gave ma one extra idea let me see when I have time to sketch it.
@William_L_DeRieux_IV there isn’t much more to show/say that my explanation above: I have to create a thumbwheel around two jammed nuts. Imagine a threaded rod that I have to create a way to engage it in rotating.
@Florian_Ford What if you just used a ratcheted open box wrench?
My dad did just that to adjust a screw for some wood-working equipment.
@William_L_DeRieux_IV That is an option but usually I would do the jammed nut stack and leave it like that. This is for a bed adjustment system (for a 3d pritnter) and it would look better with a thumbwheel.
@Florian_Ford
Amazon has some ready made plastic knobs
you might want to look at to get some ideas:
https://www.amazon.com/s?rh=n:16412851,p_n_feature_seven_browse-bin:5485604011
maybe even use this style (designed for a lathe):
https://www.amazon.com/s?rh=n%3A16412851%2Cp_n_feature_seven_browse-bin%3A5485604011
@Florian_Ford In the modification I suggested, the wheels would not fall, as there would be a thin layer above the bottom wheel that prevents the nut from falling out and a thin layer below the top wheel. I’m looking forward to seeing your new design. I quite enjoy these thinking projects.
Hmm, as much as I like to thinker with concepts and design stuff, a simpler (maybe the simplest) would be just a wheel in between the two nuts, who don’t have to be jammed against each other this time, the in-between plastic wheel would be threaded so that when turned it will not be able to screw-unscrew on the bolt because of the two nuts that are already there … I would just need for space purposes the thinner variation of nuts (jamnuts?)
Edit: @Fred_U I believe this is exactly what you explained am I right?
Made a quick design:
The nuts will not need very tight fastening against the plastic in between them in order to prevent crushing it and for light duty applications like mine should be totally fine.
BTW, I have uploaded the first design to thingiverse (now it seems totally overkill but there where tight jamming is needed it would be a good choice): http://www.thingiverse.com/thing:1895338
If you take the first rendering in the most recent image and change the circular recess to a hex, then slice it mid-way between the space between the nuts, it’s what I had pictured. The third gear between the two wasn’t in my alleged mind. On the other hand, for light duty, low force applications as you describe, I agree that this most recent image should work.
